1. Field of the Invention
The present invention relates to metering of multiphase flow in conduits, and more particularly to multiphase metering with ultrasonic tomography and vortex shedding.
2. Description of the Related Art
Tomographic imaging of flow tends to focus in general on the imaging of two phases. The technique generally used for two phase flow reconstruction has been based upon what is known as the filtered back projection algorithm. This type of flow reconstruction is described for example by Kak, Avinash C., Slaney, Malcolm “Principles of Computerized Tomographic Imaging,” IEEE Press, New York, USA (1988), and Murrell, H. “Computer-Aided Tomography,” The Mathematical J. V6 (1996), pp. 60-65.
However, because of the nature of the fluids present in production of oil and gas, it is necessary to form images of three phase flow in conduits involved in hydrocarbon production. Because of the different fluid properties of water (brine), oil and gas it is difficult to address all three sets of fluids simultaneously. In the case of oil-water or water-oil multiphase flows, the medium has been utilized. In the case of liquid-gas or gas-liquid flows (where the liquid is brine or oil or both) an attenuation approach has been utilized. As far as is known, neither method, however, has provided a wholly satisfactory picture of a three phase multiphase flow cross section.